Field of the Invention
The present invention relates to a method for separating a specific gas using a gas separation membrane module.
Description of the Background Art
In recent years, as a process for separating a specific gas, such as carbon dioxide, from synthetic gases synthesized in plants for the production of hydrogen, urea, or the like, natural gases, exhaust gases, and the like, a gas membrane separation process has been attracting attention for being capable of realizing energy saving.
In a gas membrane separation process, a raw gas containing a specific gas to be separated is fed to the feed side of a gas separation apparatus including a gas separation membrane. As a gas component that permeates through the gas separation membrane, the specific gas is separated and recovered. In terms of the recovery rate and throughput of the specific gas, usually, the driving force for gas permeation (e.g., the working temperature and working pressure of the gas separation apparatus, the permeate pressure difference, etc.) is set relatively high (e.g., Japanese Patent No. 4965927).